By consensus Frank's The Americans is perhaps the most important photo book of the last half century even though those who don't have a clear sense of what was available before and after may not fully understand why. Indeed, his style (in its most generic sense) has become so mainstream or at least popular that his book seems quite tame, almost banal. Looking In (and the exhibit it references) is essential for understanding the context and influence of the Frank book. In the first instance it makes clear why so many of the photos in the Frank book are important and ultimately unsettling. There are lucid discussions of his choices in making, developing, and presenting the photos. It also provides a nice set of essays tracing Frank's career and the various journeys he took while making the photos. Essays on the folks who influenced him (especially Walker Evans) are quite illuminating. The volume also contains many of the pictures he took before The Americans, a bonus, as well as all those in The Americans. Thus for those who do not own the original book,this volume contains the original at relatively little extra cost (maybe $10) (but in a much larger and heavier format). The hardcover edition contains some extra material, mostly as I recall contact prints which allow comparisons of versions chosen for the book with similar ones not. For my purposes the paperback version contains the essential material and is much cheaper. The actual exhibit (which I saw in San Francisco and is now in NYC) did a nice job of explaining the sequencing of the photos (Frank was obsessed with this) and providing some insights into why certain photos are important. The exhibit notes were more focused that those in Looking In and I found the exhibit notes more helpful. However, bottom line is that this is essential reading (and looking) for anyone with more than a passing interest in modern photography, especially those who cannot see the exhibit.